1. Field of the Invention
The present invention relates to a method of quantifying an external event core damage frequency (CDF) assessment of a nuclear power plant, and more particularly, to a single quantification method of an external event probabilistic safety assessment (PSA) model containing multi-compartment propagation scenarios by which an external event CDF assessment is quantified in consideration of external events occurring in single compartments and external events spreading to adjacent compartments.
2. Description of the Related Art
A nuclear power plant is divided into 200 or more compartments so as to be managed. Also, quantifications of 200 or more times should be performed on 200 or more compartments in order to quantify core damage frequencies (CDFs) which may be induced by damages to equipments installed in 200 or more compartments. In addition, a fault tree is changed whenever an external event quantification is performed in each of the compartments.
In order to solve this problem, a simple method of processing and quantifying data is disclosed in Korea Patent Application No. 2007-28638 applied by the present applicant.
In the above simple method, compartment information of a nuclear power plant, an event occurrence frequency in each compartment, other parameters, and information regarding equipments and related cables that may be damaged when events occur are input in order to generate a mapping table. An external event fault tree is formed based on the mapping table in order to perform quantifications at a time regardless of the number of target compartments which are to be analyzed.
However, in the above simple method, simultaneous quantifications are performed on external events in single compartments, but external events propagated to adjacent compartments are not considered at all. The propagations of external events to adjacent compartments are very important factors in a fire PSA, a flood PSA, and the like. Compartments, such as a switch gear compartment and the like, having an important effect on the safety of a nuclear power plant, are required to be analyzed in consideration of the propagations of external events to a corridor and adjacent compartments.